Three cases of Bartter-like syndrome in infants were reported to the Center for Disease Control on July 26, 1979. These infants were less than 10 months of age, failed to gain weight, had poor appetites, and were observed to have hypochloremia, hypokalemia, and varying degrees of alkalosis. Subsequently approximately 141 infants have been documented to have experienced the same constellation of symptoms. The common denominator in all these cases is thought to be the consumption of the same brand of soy-base formula, Neo-Mull-Soy. It was learned that this formula contained deficient amounts of chloride and infants using this formula as the sole or predominant source of food developed a severe chloride deficiency with other associated metabolic alterations. Long-term effects of chloride-deficient feedings in humans is not known and therefore a follow-up of these infants has been initiated.